Episiotomy to prevent obstetric anal sphincter injuries during instrumental delivery in nulliparous women: a national prospective comparative cohort study
Bibliographic record
Abstract
BACKGROUND: We are lacking data with a high level of evidence on the use of episiotomy during instrumental delivery to prevent anal sphincter injury, which nonetheless presents the highest risk. OBJECTIVE: Our main objective was to assess the protective effect of episiotomy against obstetric anal sphincter injury in nulliparous women during instrumental delivery according to type of instrument. We also investigated its impact on immediate maternal and neonatal morbidity. STUDY DESIGN: We conducted a prospective comparative cohort study for clinical trial emulation by means of propensity score weighting. The study was especially designed for consideration of possible confounders. This was a nationwide observational multicenter study including 111 French public and private maternity units between April 2021 and March 2022. We included nulliparous women, with singleton cephalic fetus, at more than 34 weeks of gestation. We considered vacuum, forceps, and spatula deliveries. We proceeded to a comparative analysis between women with and without episiotomy. The main outcome was obstetric anal sphincter injury occurrence. We used composite criteria for both maternal and neonatal immediate morbidity. RESULTS: The analyses pertained to 11,013 women. Overall prevalence of episiotomy was 23%: 17% for vacuum (N=7007), 37% for forceps (N=2378), and 29% in case of spatula-assisted (N=1628) delivery. Episiotomy was not associated with significantly decreased obstetric anal sphincter injury occurrence in vacuum delivery (from 5.2% without episiotomy to 3.8%, odds ratio=0.73 [0.48-1.03]) or forceps delivery (from 10.9% without episiotomy to 8.8%, odds ratio=0.81 [0.56-1.14]). In contrast, we observed significantly decreased obstetric anal sphincter injury occurrence (from 9.4% without episiotomy to 5.6%) in spatula delivery (odds ratio=0.60 [0.37-0.87]). Episiotomy was associated with increased maternal morbidity using forceps (from 13.6%-18.3%, odds ratio=1.35 [1.01-1.73]) and spatulas (from 9.0%-13.4%, odds ratio=1.51 [1.11-2.00]). We also observed increased neonatal morbidity in vacuum delivery associated with episiotomy (from 9.1%-13.6%, odds ratio=1.49 [1.21-1.79]), but a decrease in case of forceps delivery with episiotomy (from 12.6%-9.2%, odds ratio=0.74 [0.55-0.95]). CONCLUSION: Episiotomy was not associated with a decreased risk of obstetric anal sphincter injury in vacuum or forceps delivery, and a marginal reduction was achieved using spatulas. Our results do not favor extensive episiotomy during instrumental delivery. TRIAL REGISTRATION: ClinicalTrial NCT04446780.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".